Electric fuse and cut-out.



YPATENTED DBC. 6, 1904-.

E. E. GLOVEE. EEEGTEIG EUsE AND CUT-OUT.

APPLICATION FILED AUG. 13. 1903.

' N0 MODEL.

Wil/2776696 fwwf UNITED STATES Patented December 6, 1904.

PATENT OEEICE.

BENJAMIN H. GLOVER, OF BUFFALO, NEIV YORK, ASSIGNOR TO CHICAGO FUSE WIRE AND MANUFACTURING COMPANY, OF

CHICAGO, ILLINOIS.

ELECTRIC FUSE AND CUT-OUT.

SPECIFICATION forming part of Letters Patent No. 776,660, dated December 6, 1904.

Application led August 13, 1903. Serial No. 169,376. (No model.)

Be it known that I, BENJAMIN H. GLovEn, a citizen of the United States, residing at Buffalo, in the county of Erie and State of New York, have invented new and usefulImprovements in Electric Fuses and Cut-Outs, of which the following is a specification.

This invention relates to safety fuses or cut-outs of that kind which are included in electric circuits for the protection of instruments therein from currents of abnormal strength and which consists of a fusible conductor and an inclosing case, wrapper, or envelop containing a finely-divided or pulverized material which insulates and protects the fuse from injury and acts to modify or muflie the force of the explosion and diffuse, absorb, or

otherwise affect the gases or vapors upon a disruption of the fuse.

One object of the invention is to provide an inclosing wrapper or envelop for the fusible conductor which will thoroughly diffuse or distribute the force of the disrupting eXplosion and gases evolved thereby and preclude injury to person or property.

Another object is to provide a reliable practical fuse element of inexpensive construction which is an article complete in itself and can be supplied independently of the ordinary tubular protecting-case.

In the accompanying drawings, Figure l is an elevation of a fuse element embodying the invention. Fig. 2 is a perspective view of the fusible cond uctor-and sheet and powdered material from which the envelop or wrapper is formed, showing the manner of forming the latter. Fig. 3 is a transverse central section of the fuse element on an enlarged scale. Fig'. A is a fragmentary longitudinal section, on an enlarged scale, of one end of the fuse element. Fig. 5 is a longitudinal sectional elevation of the fuse and its inclosing tubular case. Fig. 6 is a fragmentary perspective View of the wrapper-sheet and loose packing or filling for the tubular case. spective view showing a sheet and fusible conductor of somewhat different form. Fig. 8 is a Fig. '7 is a pertransverse section, on an enlarged scale, showing a fuse element of another construction.

Like letters of reference refer to like parts in the several figures.

A represents the conductor, which preferably consists of a central strip or wire of any suitable fusible metal or alloy, connected at its opposite ends to wires or pieces of relatively higher conductivity. The conductor may, however, consist in whole of the fusible material, and the latter, whether constituting the entire conductor or not, may be of any shape in cross-section-for instance, in the O form of a round wire, as shown in Figs. l to 6, or of a thin iiat strip, as shown in Fig. 7. The wrapper or envelop which surrounds the conductor consists of a sheet B of insulating material, preferably paper, and a iinely-divided or powdered material C, which is coniined or retained about the conductor by the wrapper or envelop sheet. The powdered material should be of a non-conducting refractory nature, containing little or no silica, 7 O

in order to prevent the formation of a slag or glass by the combination of the silica with the vapors of the fused metal when the fuse is disrupted. BoraX, carbonate of soda,

slaked lime, and other materials give good results. In making the fuse element the powdered material is preferably spread in a thin layer on the 'flat envelop or wrapper sheet, and the conductor is laid crosswise of the sheet over the powdered material, as shown in Fig. 8O

wrapper consisting of alternate layers or convolutions of the sheet material and the powdered material.

In the construction shown in Figs. 2 and 4 the wrapper-sheet is provided at or near its opposite edges with narrow strips D of comparatively thick paper or other suitable material, which are pasted or otherwise secured to the wrapperesheet. Blotting-paper answers well for this purpose. These strips retain or confine the powdered material between them and prevent its escape from the wrapper and also serve to separate the central or main body portions of the convolutions of the wrapper to prevent the formation of too dense a roll and at the same time afford the necessary stidness or compactness of the w apper at its ends to enable it to be [irmly and permanently held in proper form by binding strips or devices E. The latter are preferably metal staples, clips, or strips, which are bent around the ends of the wrapper or envelop, as shown in Figs. l to 4, to tightly compress and hold the same. Binding devices or methods of binding of any other suitable character may be employed.

Instead of providing' the envelop or wrapper sheet with the separate retaining-strips D, as just explained, the end edges of the sheet can be folded or turned over toward each other, as indicated at F in Fig. 7. The folded edges will confine the powdered material and provide density and compactness for the ends of the wrapper.

The fuse element thus constructed of the conductor and surrounding wrapper or envelop is preferably inclosed in the usual protecting tubular case G, Fig. 5. The protecting-case ordinarily consists of a tube of vulcanized liber or analogous stiff` insulating material and end caps or heads g, of brass or other metal, which are detach-ably secured by screws or otherwise to the tube. The ends of the conductor are inserted in central holes in the end caps, to which they are secured by soldering or otherwise. The end caps may be provided with vent holes or perforations for the escape of the gases or vapors evolved by the melting of the fuse. The body of the protecting-case may, however, consist of a hard paper, fiber, or other insulating-strip G', attached to or formed on the end of the wrapper-sheet and rolled up therewith to form one or more of the outermost convolutions of the wrapper or envelop. rlhis construction is shown in Fig. 8.

H represents a loose packing or filling material, preferably asbestos fiber, which is inserted in the ends of the protecting-ease between the end caps and the ends of the wrapper or envelop for the conductor for the purpose of retarding or mufliing the escape of the gases or vapors. This packing material may be loosely placed in the ends of the protecting-case; but it is preferably secured to the wrapper or envelop for the conductor, (as shown in Fig. 6,) so that it constitutes a part of the fuse element and is inserted in and removed from the protecting-case with the fuse element. For this purpose each end edge I of the wrapper-sheet projects for a short distance beyond the powder-retaining strips D, and the loose packing or filling material H is placed on the projecting edges of the wrapper-sheet and rolled or wound with the latter about the conductor, the packing' material being held between the convolutions of thc wrapper.

rlhe fuse is included in the electric circuit in the usual manner. For instance, the metallic end caps of the protecting-case are inserted in contact-clips, or the inclosing case is provided with connecting devices of any suitable form. The connecting devices constitute no part of the invention and are not shown.

It has been found that the powdered filling of the wrapper must be loosely placed therein for best effect in suppressing the electric arc accompanying the disruption of the fuse. It, however, occurs that through shipping and handling of these fuses this powdered material becomes packed, accompanied usually by certain crevices and cracks, and it is through these cracks that the gases are enabled to escape as a whole, with attending disastrous results, instead of being disseminated throughout the mass of the powdered material. l have, however, found that when the powdered. material is placed in successive layers, although it may become packed and may have therein the crevices and cracks, yet these crevices and cracks in the different layers never register, so that the discharge that escapes through one .layer is arrested by the next, and so on until it is suppressed without ill effects to the fuse as a whole.

rlhe wrapper or envelop described adequately protects and insulates the fusible conductor and when the latter is disrupted thoroughly diffuses or disseminates the gases or vapors evolved by the fusion of the conductor. The pulverized material being conlined between the successive convolutions of the wrapper-sheet separates the latter, and when the conductor is disrupted it often appears that the wrapper is not broken at one point only, but is torn or ruptured throughout an cxtended area, and thus greatly decreases the force of the explosion. As the convolutions of the wrapper separate the pulverized material into separate layers or strata, the evolved gases or vapors cannot blow out the pulverized material at one point, and thus defeat the intended action of the pulverized material; but the gases or vapors are distributed or divided and caused to escape in the form of a multitude of [ine streams or jets, and thus encounter successive layers or groups of lilling. '.lhe wrapper or envelop is formed on and supported by the conductor, whereby elements consisting' of the conductor and wrapper can be supplied as an article of manufacture and sold with or without the protecting-case, as found most expedient or desirable.

It is understood that the scope of this invention is not necessarily confined. to the exact details of construction shown herein, nor, furthermore, to the exact relations of the various features; but these relations may be altered and some may be used without the others, and the invention extends to such use.

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I claim as my invention- 1. An electric fuse or cut-out element comprising a conductor, and a wrapper or envelop surrounding said conductor and having a plurality of thicknesses, and a powdered material between the thicknesses of the wrapper, substantially as set forth.

2. An electric fuse or cut-out element comprising a conductor, and a wrapper or envelop of spiral form surrounding said conductor and having powdered material between the convolutions of the wrapper, substantially as set forth.

3. In an electric fuse or eut-out, the combination with a tubular case, of a conductor therein consisting in whole or in part of a safetyfuse, and a wrapper or envelop in successive layers around said conductor, the said wrapper or envelop containing a powdered material in contact with the fuse, substantially as set forth.

4C. In an electric fuse or cut-out, the combination with a tubular ease, of a conductor therein consisting in whole or in part of a safetyfuse, and a wrapper or envelop spirally wrapped in successive layers around said conductor, said wrapper or envelop containing' a powdered material in contact with the fuse, substantially as set forth.

5. In an electric fuse or cut-out, the combination of aconductor consisting in whole or in part of a safety-fuse, and a wrapper or envelop of sheet material in successive layers and having inclosed ends surrounding said conductor, said wrapper or envelop containing' a powdered material in contact with the fuse, substantially as set forth.

6. In an electric fuse or cut-out, the combination of a conductor consisting in whole o1' in part of a safety-fuse, and a wrapper or envelop of sheet material in successive layers with thickened edges surrounding said conductor, said wrapper or envelop containing a powdered material, substantially as set forth.

7. In an electric fuse or cut-out, the combination of a conductor consisting in whole or in part of a safety-fuse and a wrapper or envelop of sheet material in successive layers with interposed strips supported on said conductor, said wrapper or envelop containing a powdered material, substantially as set forth.

8. In an electric fuse or cut-out, the combination with a tubular case, of a conductor therein consisting' in whole or in part of a safetyfuse, and an envelop of paper spirally wrapped in successive layers with interposed strips independent of the tubular case, and supported on said conductor, said independent envelop containing a powdered material in contact with the fuse, substantially as set forth.

9. In' an electric fuse or cut-out, the combination with a tubular c'ase, of a conductor therein consisting' in whole or in part of a safetyfuse, and an envelopindependent of the tubular case having compressed ends and supported on said conductor, said independent envelop containing a powdered material in contact with the fuse, substantially as set forth.

10. In an electric fuse or cut-out, the combination with a tubular case, of a conductor therein consisting in whole or in part of a safety-fuse, an envelop independent of the tubular case having' compressed ends supported on said conductor, and exterior binding' devices for said envelop, said independent easing containing' a powdered material in contact with the fuse, substantially as set forth.

11. In an electric fuse or cut-out, the combination of a tubular case, of a conductor thereinconsisting in whole or in part of a safety-fuse, and an envelop of sheet material in successive layers with powdered material between the layers supported on said conductor independently of said tubular case, said independent envelop containing' a powdered material in contact with the fuse, substantially as set forth.

12. In an electric fuse or cut-out, the combination with a tubular case having' vented ends, of a conductor therein consisting' in whole or in part of a safety-fuse, an envelop surrounding said conductor, said envelop containing a powdered material in contact with the fuse, and a loose filling in the space between the ends of the tubular case and said independent envelop and secured to the latter, substantially as set forth.

13. In an electric fuse or cut-out, the combination with a tubular case having' vented ends, of a conductor therein consisting` in whole or in part of a safety-fuse, an envelop independent of the tubular case supported on said conductor, said independent envelop containing a powdered material in contact with the fuse, and an asbestos filling in the space between the ends of the independent envelop and the ends of said case, substantially as set forth.

14. In an electric fuse or cut-out, the combination with a tubular case having caps, and means for removably securing the caps, of a conductor therein consisting in whole or in part of a safety-fuse, and an envelop independent of the tubular case supported on said conductor, said independent envelop containing a powdered material in successive layers in contact with the fuse, substantially as set forth.

I/Vitness my hand this 11th day of August,

BENJAMIN H. GLOVER. Vitnesses:

C. B. HoRNBuoK, CHAs. W. PARKER.

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